A study of photometric variations on the dwarf planet (136199) Eris R. Duffard, J. L. Ortiz, P. Santos Sanz, A. Mora, P. J. Gutiérrez, N. Morales and D. Guirado A&A, 479 3 (2008) 877-881 Published online: 18 December 2007 DOI: 10.1051/0004-6361:20078619